The control of the characteristics of the fluid pumping process in modern pumps is provided in manual and automatic modes. Depending on the requirements for operation, it may be necessary to take into account certain parameters. For example, the user can adjust the feed volumes and the intensity of the function. However, there are certain types of equipment that are specifically designed for the point service of certain environments. These include dosing pumps used in the food, pharmaceutical and chemical industries.
Features of dosing pump
Dosing units provide the possibility of volumetric pressure pumping of liquids, suspensions and emulsions. However, most of these pumps can serve both neutral and aggressive environments. For this reason, their use is common in the chemical industry. Depending on the characteristics of the material used in the flow part, the specific purpose of the equipment is determined. The main difference from traditional household units is that dosing pumps allow you to adjust the pressure level from the exit point to the entrance of the working medium. In this case, the absolute indicator of the inlet pressure exceeds the similar indicator of the saturated vapor of the pumped liquid. Among the main technical and operational characteristics of such equipment, the ability to work with media of a certain kinematic viscosity and the diameter of the passage of the nozzles is noted.
Hose metering pumps
This type of metering pump is designed to work with liquids and pasty substances. The principle of operation is based on mechanical action on the working channel, which is most often represented by a strong but flexible tube. That is, during operation, mechanical pressure is applied to the hose with the medium, as a result of which the liquid is pushed to the outlet. As a physical activator, rollers rolling around the circumference are used. By design, metering pumps of this type are a device including flexible pipes and a hose with a set of rollers. Also, the infrastructure part is provided by the track into which the tube line is laid. It is in him that the physical effect occurs.
Diaphragm units
This is a volumetric pump in which a flexible plate fixed at the edges of the structure performs the function of the working body. To a certain extent, it acts as a piston. The membrane bends during operation, which leads to fluid displacement. In this case, the force impact can be different. For example, it is practiced using mechanical drives, hydraulics, and pneumatic devices that deform the plate by changing the pressure in the working cavity. Due to the absence of gearboxes and motors, metering pumps are considered the safest and most reliable. This is especially important in the maintenance of flammable liquids, since the function of the unit has no prerequisites for the formation of a spark.
Plunger models
This is a type of reciprocating hydraulic machines based on reciprocating movements. The valve distribution system does not allow the use of such units for reverse action, which distinguishes them from other volumetric devices. The reverse movement of the piston in the pipeline leads to the closure of the valve, which prevents the leakage of medium into the channel. At the same time, the valve on the discharge side opens, and through it, the liquid escapes to the receiving point. During operation, the metering plunger pump provides an uneven fluid velocity, which causes its main drawback. The spasmodic effect is compensated for in various ways, including by introducing several piston elements into the design.
Unit marking
If the structural design of the units are carried out in accordance with the requirements of a specific form factor, then in terms of functional content and controls mechanisms, manufacturers develop common standards. So, the ND metering pump provides for manual regulation of fluid transfer from the moment the unit stops. If the system is provided with the possibility of automatic and remote monitoring, then the equipment is assigned the designation NDE.
Also, manufacturers indicate a dosing index, which averages 1-2.5. There are also devices in which this indicator is not observed at all. As a rule, models with an initial index do not have a heating jacket, and the highest level of metering accuracy is characterized by the presence of a shut-off or flushing fluid in the supply design. This classification also applies to all types of aggregates. For example, a metering plunger pump ND can have both a first accuracy index and a second.
Manufacturer's Reviews
Dosing models in the families of pumping equipment occupy a separate niche due to the specifics of their application. This is not a household segment, therefore, such units do not have wide distribution among manufacturers themselves. The development in this direction is carried out by large specialized companies, including Etatron and Grundfos. In the assortment of the first manufacturer, the modification eOne Basic gained popularity. This is a membrane unit, the users of which note the presence of a well-thought-out intelligent control system with the possibility of high-precision power control. Grundfos metering pumps, and in particular diaphragm representatives of the DME series, are no less worthy of presentation. Owners of such equipment emphasize reliability, successful performance of ball-type valves, as well as the function of an electronic unit that allows you to adjust the metering accuracy.
Conclusion
The segment of metering pumping equipment can be attributed to industrial, since such devices are more often used at enterprises, in service organizations, etc. This also explains the high requirements for the design part. Reliability, safety and stability - these are the main qualities that modern dosing systems should have. Pumps of this type operate in intensive operation, and therefore manufacturers are striving to increase the resource of the element base. Among the negative factors distinguish not only the ordinary wear of mechanical parts. For example, membrane units have virtually no rubbing components. But the flow part in contact with aggressive media must be protected from chemical attack.